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Author Topic: Simspeed UWD LSR Design Project  (Read 19071 times)

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Offline SPARKY

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Re: Simspeed UWD LSR Design Project
« Reply #90 on: August 01, 2019, 12:29:38 PM »
my experience is you are looking past/through the yaw string-- your visual  image input changes on/of the horizon change was definitely easier/sooner to pick --operates much like a range when on the water.But you need fixed objects on ones horizon
Miss LIBERTY,  changing T.K.I.  to noise, dust and RUST!!!

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Offline Rex Schimmer

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Re: Simspeed UWD LSR Design Project
« Reply #91 on: August 01, 2019, 01:13:57 PM »
There is a new streamliner that will probably be able to provide some input on this question. I am expecting this car to be very fast at Speed Week.

Rex
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Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #92 on: August 01, 2019, 02:23:35 PM »

     I have followed LSR since the late 50's and finally getting to experience being there in '71 & '72,  then again in '08.  From my actual observations, seeing pictures and reading about conditions before and since, I'll say that the  salt surface conditions have changed DRASTICALLY since the time of Cobb's, Campbell's, Breedloves's, Summer's runs and those of others back then.  Current conditions should be a MAJOR factor in any present attempt equations.

    I've found this a very interesting project to follow, stay with it and all my best for your success!

                    Ed   
Hi Ed,
Thanks for your encouragement.  I'm sure you're assessment of the salt and its influence on today's racers is correct.  It's a real shame that the salt flats have been allowed to deteriorate as they have.  The state should have stepped in earlier to help preserve what I consider a national treasure.  Where are the eco-activitist when we need them?  Thanks... Terry

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #93 on: August 01, 2019, 02:27:11 PM »
There is a new streamliner that will probably be able to provide some input on this question. I am expecting this car to be very fast at Speed Week.

Rex
That's certainly an interesting design Rex.  I was quite intrigued the first time I saw it.  Do you know what the drive train consist of?  Are there any links to the builder?  What's the name so I can look to see what I can find out about it?  Thanks... Terry

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #94 on: August 01, 2019, 05:08:18 PM »
The potential problem I am describing has nothing to do with suspension travel or side-to-side movement at the Heims.  It has to do with the limited resistance to rotation about the axis between the upper and lower Heims at the narrow ends of the A-arms.  Given mechanical clearances and elasticity, the narrow spacing of the upper Heim pair cannot be considered a rigid connection in a steering rotation sense, but rather just an upper pivot point.  The front wheel assembly is effectively mounted on a kingpin with dubious steering rotation stiffness.

IO,
Giving consideration that you are making a valid point that I'm just not understanding in the context of your argument, let me provide some illustrations to better clarify what I am thinking when I read your points.  The number #10 image below shows your description of "rotation about the axis between the upper and lower Heims at the narrow end of the A-arms".  The 3 green directional arrows show the axis I believe you are describing since you said side to side movement is not in question.  The two yellow components are the spindles centered on the top and bottom king pins affixed to what I describe as the ?steering knuckle?. If that term is foreign to you what would you like to call it?  The vertical and horizontal black lines represent the center lines of the spindles through the king pins and center axis. 

When you say "the front wheel assembly is effectively mounted on a kingpin with dubious steering rotational stiffness" are you not describing virtually all common steering/spindle/kingpin configurations whether mounted to a-arms or bosses welded to solid axles?  Even struts act as the spindle where the top and bottom connections swivel about a centerline which serves the kingpin role.  Would the single connection point of the kingpin at an a-frame also be considered dubious based on your description here?  Why would two heim connection points be any more dubious than the one common ball joint connection at an a-frame?

Where is the "dubious steering rotational stiffness" you are describing?  Is it the king pin mounting bosses coming off the steering knuckle?  Are you saying those points have movement because the knuckle itself is held in place by the a-arms at their two heim connecting point?  Exactly where is the center and plane of the dubious rotational axis?  If its the plane represented by the 3 green arrows?  Where does the dubious rotation come into play?

So, lets say we have no front suspension and the steering knuckle is solid mounted to the frame as represented in attachment #11.  Here the knuckle is mounted at the same 4 flanges, two top and two bottom.  Do you still see dubious rotational stiffness when the spindles are steered left and right through the tie rod?

Attachment #12 shows the 6 degree extent of spindle movement to the right and inversely the same to the left.  Because this is a zero scrub radius steering setup I don't see the steering load on the steering knuckle which is a 110mm x 40mm cross section x 420mm diameter solid chunk of metal as a dubious component.  Neither do I see the connection points of the a-frames as questionable.  I might believe the a-frames themselves could be beefier but considering the low impact application of running up and down the salt I don't think so. But as always I could be wrong.   The yellow spindles will likely need to be beefier in real use but I'm not trying to engineer structural integrity in these drawings.  This is currently just a concept exercise.  Please help me to understand if you can what I am missing about your argument.  Thanks... Terry
« Last Edit: August 01, 2019, 05:15:58 PM by Simspeed »

Offline Interested Observer

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Re: Simspeed UWD LSR Design Project
« Reply #95 on: August 01, 2019, 06:07:02 PM »
Draw a line in 3-space from the upper Heim pair to the lower single Heim.  That is the axis, somewhat inclined from vertical, about which the whole thing is likely to rotate to some degree--the orange piece, yellow pieces, motors, wheels, tires etc.  If you were to grab the tires from the side and tried to steer them, they would wobble about that axis.  Resulting from dubious steering rotational stiffness.

Offline Stan Back

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Re: Simspeed UWD LSR Design Project
« Reply #96 on: August 01, 2019, 06:38:41 PM »
B/BGS      Eddie's Chop Shop, E. Umland, 8/18   369.162

   2004   Salt Shark
      2018 Custom EX7 Streamliner, 427" Chevy V-8
      Owner:  Ron Flattery ? Fremont, California
      Driver:  Tom Flattery
      Crew Chief:  Beth Zeigler 
      Crew:  Ed Flattery, Sharon Sam, Todd Hamor


Member of the San Berdoo Roadsters -- "California's Most-Exclusive Roadster Club".
Celebrating 67th anniversary of racing on the salt.

Offline sockjohn

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Re: Simspeed UWD LSR Design Project
« Reply #97 on: August 01, 2019, 08:09:09 PM »
There is a new streamliner that will probably be able to provide some input on this question. I am expecting this car to be very fast at Speed Week.

Rex

I assume that is front wheel drive?

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #98 on: August 01, 2019, 09:35:35 PM »
Draw a line in 3-space from the upper Heim pair to the lower single Heim.  That is the axis, somewhat inclined from vertical, about which the whole thing is likely to rotate to some degree--the orange piece, yellow pieces, motors, wheels, tires etc.  If you were to grab the tires from the side and tried to steer them, they would wobble about that axis.  Resulting from dubious steering rotational stiffness.

IO...Is this the line the axis you claim the knuckle and all other attached components are "likely" to rotate to "some" degree? (see attached)

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #99 on: August 01, 2019, 10:10:49 PM »
B/BGS      Eddie's Chop Shop, E. Umland, 8/18   369.162

   2004   Salt Shark
      2018 Custom EX7 Streamliner, 427" Chevy V-8
      Owner:  Ron Flattery ? Fremont, California
      Driver:  Tom Flattery
      Crew Chief:  Beth Zeigler 
      Crew:  Ed Flattery, Sharon Sam, Todd Hamor

Thanks for the info Stan.  Their FB page has all the build pics and good posts and comments from fans.  Interesting that he has a turbo 400 auto transmission in it.  I'm assuming they're not running the torque converter. Thanks... Terry

Offline Interested Observer

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Re: Simspeed UWD LSR Design Project
« Reply #100 on: August 02, 2019, 08:09:39 AM »
Quote
IO...Is this the line the axis you claim the knuckle and all other attached components are "likely" to rotate to "some" degree? (see attached)
Yes, that is it.  I now note that in that illustration there are two lower Heims, which would improve the situation somewhat, but it is still open to question how stiff the arrangement would be.  Originally, working from LSR 5.3.9.JPG, it appeared there was only one lower pivot point.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #101 on: August 02, 2019, 04:27:04 PM »
Yes, that is it.  I now note that in that illustration there are two lower Heims, which would improve the situation somewhat, but it is still open to question how stiff the arrangement would be.  Originally, working from LSR 5.3.9.JPG, it appeared there was only one lower pivot point.

Well I'm glad we were able to boil this down to simply a misinterpretation of what the illustrations were showing IO.  I believe stiffness is a function of geometry and structural integrity of components.  In this example both items were addressed sufficiently for the intended case based on my past experience with similar fabrications of tubular drag suspensions.  If we are able to move to a development stage all of these systems will be formally engineered.  I'm hoping that will come to pass.  Thanks for helping to sort this out... Terry

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #102 on: August 03, 2019, 05:14:35 PM »
By refining the body geometry and re-configuring the chassis somewhat I was able to lower the frontal area another 10% to 4.774 sq.ft.  Without the active aero wing FA drops just under 4 sq.ft. again.  This body is much cleaner and better reflects what I'm hoping to achieve for this project.  I'm unsure which will be the better combination...more downforce at the expense of FA; or no active downforce and a 10% drop in NA.  I know weight is needed for traction but I'm not happy with adding a lot of ballast to get it.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #103 on: August 03, 2019, 05:26:50 PM »
I borrowed from Eddie of Eddie's Chop Shop for the exhaust collectors.  His successful design and application of the heat spreading exhaust port is very impressive and works well for this relatively straight sided design.  By turning the IC/Gens upright like an outboard motor I was able to make better use of the available space to tighten up the width of the car while keeping the same track width as V.5.3.

On the subject of aero downforce would it be better to install a flat plate to the top of the body instead of the wing as shown?  The plate would tilt up like some jet air air brakes via the same hydraulic ram to expose more area to the airstream for downforce to gain traction for greater speed.  As with the current wing design the angle of the plate would be auto adjusted with the traction control to provide downforce as needed for traction.  Your thoughts... Terry

Offline tortoise

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Re: Simspeed UWD LSR Design Project
« Reply #104 on: August 03, 2019, 06:27:36 PM »
I've been studying the published FIA regulations as they relate to some of the questions that have come up in the discussion of this evolving concept. A few things I've noticed:

Per section D2.4.2, it looks like it's not a hybrid by their definition.

I can't find anything disallowing movable aero for category A (automobiles) although there is a specific entry allowing same for "Special" automobiles, apparently meaning rockets and jets, so maybe that  implies their prohibition for just plain automobiles. This may be irrelevant, however, because of section D4.2.7, which establishes an Absolute World Wheel Driven Record. 

Does anybody know anything for sure about this?